Many LED light bulbs have a look which is different from the traditional incandescent light bulbs. Most of the conventional LED light bulbs are in a semi-sphere configuration, due to the addition of a barrel-shaped heat sink arranged at one end. Compared to the traditional incandescent light bulbs, the heat sink of the conventional LED light bulb may occupy almost one-half of the volume size, leaving a smaller available space to build in other components. It thus brings the limitation to the structural design for the LED light source of the LED light bulb, causing difficulty in achieving wide-angle emission.